This article takes issue with Kuhn’s description of the ‘Aristotle experience,’ an event that took place in 1947 and that he retrospectively characterized as a revelation that instantly delivered to him the key concepts of The Structure of Scientific Revolutions (1962). We trace a certain transformation of this narrative over time: whereas it commenced from a description of his impression of disparity between the textbook image of science and the study of historical sources, Kuhn started to characterize it as a (...) revelation after learning of the English translation of Fleck’s 1935 Entstehung und Entwicklung einer wissenschaftlichen Tatsache. This book anticipates many central Kuhnian claims. Kuhn read it as early as 1949, but never fully acknowledged it as a source of inspiration. We discuss four hypotheses concerning the possible influence of Fleck’s theory on Kuhn’s in light of the available evidence. We conclude that the degree of similarity between them is too great to be coincidental. (shrink)